wrote:
I need a new flapper for my Fluidmaster flush valve - anyone know where
I can get one online with cheap postage?

Thanks

I know where you can get one online:

Part number 16268
Replacement Flapper for P/Ns 17061, 15888, and 17501
http://www.bes.ltd.uk/

Flapper is £5.83 inc. VAT, delivery charge is £5.82 inc. VAT, giving a total
cost of £11.65.